Ink jet printers having one or more ink jet heads for projecting drops of ink onto paper or other printing media to generate graphic images and text have become increasingly popular. To form color images, ink jet printers with multiple ink jet printing heads are used, with each head being supplied with ink of a different color. These colors are then applied, either alone or in combination, to the printing medium to make a finished color print. Typically, all of the colors needed to make the print are produced from combinations of cyan, magenta and yellow ink. In addition, black ink may be utilized for printing textual material or for producing true four-color prints.
In a common arrangement, the print medium is attached to a rotating drum, with the ink jet heads being mounted on a traveling carriage that traverses the drum axially. As the heads scan paths over the printing medium, ink drops are projected from a minute external orifice in each head to the medium so as to form an image on the medium. A suitable control system synchronizes the generation of ink drops with the rotating drum.
A prior ink jet head which operates in the general manner just described is disclosed in U.S. Pat. No. 4,613,875 to Le et al., assigned to Tektronix, Inc., Beaverton, Oreg.
Another prior ink jet head of the general type just described is used in the Model 4696 color graphics printer manufactured by Tektronix, Inc. The Model 4696 printer includes an ink cartridge mounting element having four cartridge openings, each of which defines a unique keyway pattern adapted to removably seat a substantially cylindrical ink cartridge having a mating fluted periphery at one end thereof. Each of the four ink colors used by the printer is contained in its own ink cartridge, with the cartridge for each particular color having a different arrangement of flanges and flutes adapted to fit the particular keyway pattern of the cartridge opening assigned to that color. Thus, the cartridge containing cyan ink, for example, can only be seated on the cartridge opening having a keyway pattern complementary to the cyan cartridge's unique flange and flute pattern. In this way, the four ink cartridges are properly indexed in the ink jet head in a foolproof manner.
Each ink cartridge opening is located above an ink reservoir which supplies ink of a particular color to an ink jet head. Thus, in a four cartridge system, there are four distinct ink reservoirs and four distinct ink jet heads. Some ink jet printers employ multiple ink cartridges, reservoirs and ink jet heads for each color. Each reservoir is provided with a hollow needle designed to pierce a mylar seal located at the bottom of the cartridge, thereby permitting ink to flow from the cartridge into the reservoir from there, typically on demand, to the ink jet head which applies the ink to the printing medium.
Despite the foregoing advancements in ink jet printer technology, as new models of cartridge-type ink jet printers are designed and new and improved ink formulations are discovered, there remains a need for a cartridge mounting system for ink jet printers which enables ink cartridges containing new ink formulations to be used universally in both new and compatible old ink jet printer models alike and yet precludes old style ink cartridges containing possibly inferior, less desirable or less versatile ink formulations from being used with the new ink jet printer model.
Therefore, a need exists for an improved ink cartridge and ink cartridge mounting system which is directed to overcoming this disadvantage.